Data suggest that women who ingest diets high in soy protein have a marked reduction in breast cancer risk and delayed onset of postmenopausal osteoporotic fractures. Soy and other vegetable proteins are also less atherogenic than animal proteins. The purpose of this study is to gather preliminary data on the effects of specific amounts of soy protein with isoflavones (phytoestrogens) on menopausal symptoms and plasma lipids and lipoproteins.